Frightening Complex Visual Hallucinations in an ElderlyPatient with Ophthalmological Pathology and Vascular Dementia

A lady in her 90s was referred to the Later Life Team (LLT) in a rural area of the United Kingdom with complex visualhallucinations (VH). She had significant ophthalmological pathology, including cataracts, a branch retinal vein occlusion, andvitreous haemorrhage. The hallucinations included seeing monkeys ripping the heads offof her cats and lions prowling thegarden. The patient was distressed by the hallucinations and believed them to be real events. Her management involved lowdose olanzapine and requesting that her ophthalmological surgery be expedited. The surgery resulted in a significant reductionin VH. A diagnosis of vascular dementia went on to be made following cognitive testing and imaging. The cognitive impairmentmay have contributed to the patient’s inability to identify her experiences as hallucinations and thus render her without insight.A review of the computed tomography (CT) scans performed prior to the patient’s presentation to our service confirmedsignificant vascular pathology including small vessel disease and lacunar infarcts. Cognitive testing confirmed a cognitiveimpairment which had gone unnoticed by her family. This case leads to an interesting discussion regarding diagnosis incomplex VH in cases of significant ophthalmological pathology but a lack of insight. Various authors have proposed theories toexplain VH; cortical release and the Perception and Attention Deficit (PAD) model are explored as possible explanations for theexperiences of this patient.